I think the best solution would be to leave decision to user. Not only
for capitals, but also for accented letters. My eSpeak knows better how
to pronounce 'Å' or 'Ã' in Polish :)

Thanks everyone for the feedback. I would like to ask those who hear
the unwanted "capital" announcements to check whether they have the
option DefaultCapLetRecognition in their Speech Dispatcher configuration
set to "none" (should be the default). If that's the case, I suspect
the problem might be in the Speech Dispatcher's espeak module, since I
believe this setting should be honoured and if it is not, it may be a
bug. I emphasize I am currently unable to check the code and track the
problem down myself so these are all just my guesses...
Also if anyone wants to play around with this option and various
synthesizers, it might give us some important information.

You must remember: eSpeak is not only synthesizer used with Orca, and
Orca is not only application using speech. If I have Orca, Yasr and some
self-made application using libspeechd, I expect same pronunciation in
all.

Yes, this is one of the major concerns which Speech Dispatcher tries to
address and this is also one more reason for having a chance to bypass
Orca's own verbalization.
Best regards, Tomas